Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
sach ty » sach y, sach tu, sach thu
vai cuu » vai cua
cay dan » cac dan, ca dan, cay lanh
day dan » day danh, dao dan, bay dan
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
lang ha » long ha
lang xa » dang xay, lang van
va nam » van nam, ha nam, va nay

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty ((lang xa) or (lang ha)) hoi. hieu va nam thuc ((day dan) OR (cay dan)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((lang xa) OR (lang ha)) hoi. hieu va nam thuc ((day dan) OR (cay dan)) vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty ((lang xa) or (lang ha)) hoi. hieu va nam thuc ((day dan) OR (cay dan)) vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((lang xa) or (lang ha)) hoi. hieu va nam thuc ((day dan) OR (cay dan)) vai cuu tre*.